Among the different types of scientific knowledge,
are likely to be modified or discarded most frequently. Long ago, in the 1600s, scientists discarded the phlogiston theory because

Answers

Answer 1

Many people in the early days of science thought that combustible stuff was made of a component called phlogiston that this substance was emitted during the burning of combustible things.

A combustible material is what?

Combustible materials are those that, when exposed to fire or heat, will ignite, burn, sustain combustion, or produce flammable gases in the form and circumstances anticipated for their application. Combustible materials include rubber, plastics, rubberized materials, and wood.

What gases are combustible?

A gas that really can ignite inside the air or with oxygen is said to be combustible. Gases like hydrogen, methane, propane, and iso-butane are examples of flammable gases. In the existence of an ignition source, a mixture containing a particular amount of flammable oxygen and gas will explode. The most common reason for gas explosion accidents is combustible gas.

To know more about combustible visit:

https://brainly.com/question/13153771

#SPJ1


Related Questions

The pH ofa 0.060-M solution of hypobromous acid (HOBr but usually written HBrO) is 4.96. Calculate Ka.

Answers

The pH of a solution can be related to the concentration of H+ ions and the dissociation constant of the acid (Ka) by the following equation:

pH = pKa + log([A-]/[HA])

where [A-] is the concentration of the conjugate base of the acid, and [HA] is the concentration of the acid.In this case, the acid is hypobromous acid, HBrO, and its conjugate base is the hypobromite ion, BrO-. The chemical equation for the dissociation of HBrO is:

HBrO(aq) ⇌ H+(aq) + BrO-(aq)

The equilibrium constant expression for this reaction is:

Ka = [H+(aq)][BrO-(aq)]/[HBrO(aq)]

We are given the concentration of HBrO and the pH of the solution, so we can calculate [H+(aq)]:

pH = -log[H+(aq)]

10^-pH = [H+(aq)]

10^-4.96 = [H+(aq)] = 7.94 × 10^-5 M

Since HBrO and BrO- are in a 1:1 ratio at equilibrium, [BrO-(aq)] is also 7.94 × 10^-5 M. Substituting these values in the equilibrium constant expression, we get:

Ka = [H+(aq)][BrO-(aq)]/[HBrO(aq)] = (7.94 × 10^-5)^2 / (0.060 - 7.94 × 10^-5) ≈ 2.6 × 10^-9

Therefore, the value of Ka for hypobromous acid is approximately 2.6 × 10^-9.

To know more about concentration refer here

https://brainly.com/question/10725862#

#SPJ11

what predominant intermolecular force is in nh3? br2 i2 br2

Answers

The predominant intermolecular force in [tex]NH_{3}[/tex] (ammonia) is hydrogen bonding.

This is because [tex]NH_{3}[/tex] contains a hydrogen atom bonded to a highly electronegative nitrogen atom, resulting in a highly polar molecule.

Hydrogen bonding occurs between a hydrogen atom in a polar molecule and a highly electronegative atom (in this case, the nitrogen atom in another [tex]NH_{3}[/tex] molecule).

This type of intermolecular force is stronger than the other two main types of intermolecular forces, which are London dispersion forces and dipole-dipole interactions.

Bromine ([tex]Br_{2}[/tex]) and iodine ([tex]I_{2}[/tex]) are both nonpolar molecules and only have London dispersion forces between them.

To know more about intermolecular force, refer here:

https://brainly.com/question/9007693#

#SPJ11

consider the following gaussian function (which has just one adjustable parameter, ) as a trial function in a variational calculation of the hydrogen atom

Answers

In a variational calculation of the hydrogen atom, a Gaussian function with one adjustable parameter can be used as a trial function.

The Gaussian function is a commonly used mathematical function that has a bell-shaped curve, which can be adjusted by changing the value of the parameter.

By using this function as a trial function, we can approximate the wavefunction of the hydrogen atom and calculate its energy using the variational principle.

The variational principle states that the energy of any approximate wavefunction will always be greater than or equal to the true energy of the system.

By minimizing the energy of the Gaussian function with respect to its adjustable parameter, we can obtain an estimate of the ground state energy of the hydrogen atom.

To know more about Gaussian function, refer here:

https://brainly.com/question/31002596#

#SPJ11

in which type of hybridization is the angle between the hybrid orbitals 109.5o?

Answers

In the type of hybridization known as sp³ hybridization, the angle between the hybrid orbitals is 109.5 degrees. In this hybridization, one s orbital and three p orbitals combine to form four equivalent sp³ hybrid orbitals, which are arranged in a tetrahedral geometry around the central atom, resulting in bond angles of approximately 109.5 degrees.

In sp³ hybridization, one s orbital and three p orbitals of the central atom combine to form four hybrid orbitals that are arranged in a tetrahedral shape. In order for an atom to be sp³ hybridized, it must have an s orbital and three p orbital. These hybrid orbitals are used to form bonds with other atoms or groups of atoms. Examples of molecules that exhibit sp³ hybridization include methane (CH₄), ethane (C₂H₆), and ammonia (NH₃).

for more questions on hybridization: https://brainly.com/question/19538722

#SPJ11

Consider the following reaction. Would each of these changes increase or decrease the rate of reaction? All statements will be sorted. 3H2 + N2 --> 2 NH3 Increase rate Decrease rate No Answers Chosen No Answers Chosen Possible answers Removing H2 Adding N2 Adding a catalyst Lowering temperature Raising temperature

Answers

Answer:

Yes it increase the Rate of chemical reaction

Removing H2 - Decrease rate; Adding N2 - Increase rate; Adding a catalyst - Increase rate; Lowering temperature - Decrease rate; Raising temperature - Increase rate.


1. Removing H2: Decrease rate. This reaction is a synthesis reaction, which means that the reactants are combining to form a product. If one of the reactants is removed, there are fewer particles available to react, which means the rate of reaction will decrease.


2. Adding N2: No change. The balanced equation shows that there is already enough N2 present to react with the available H2. Adding more N2 will not increase the rate of reaction.


3. Adding a catalyst: Increase rate. A catalyst is a substance that speeds up the rate of a reaction without being consumed in the reaction itself. In this case, a catalyst would provide an alternative pathway for the reaction to occur, which would lower the activation energy required for the reaction to take place. This would increase the rate of reaction.


4. Lowering temperature: Decrease rate. This reaction is exothermic, which means it releases heat. According to the Arrhenius equation, as temperature decreases, the rate of reaction decreases as well. Lowering the temperature would therefore decrease the rate of reaction.


5. Raising temperature: Increase rate. As mentioned above, the Arrhenius equation states that increasing temperature increases the rate of reaction. This is because the increased kinetic energy of the particles leads to more frequent and energetic collisions between particles, which increases the likelihood of successful collisions and therefore increases the rate of reaction.

To learn more about rate of reaction visit:

brainly.com/question/30546888

#SPJ11



Calculate the molality of a solution containing 26.489 g of ethanol (CH3CH2OH) and 395 g of water.Group of answer choices0.687 m1.46 × 10−3 m1.46 m227 m0.227 m

Answers

Answer:

1.46 M

Explanation:

M = mol ÷ Liters

26.489 / 46 = .576 mol of ethanol

density of water is 1g/ml, so the amount of liters of water (L) is 395 ÷ 1000 = .395 Liters

.576 ÷ .395 = 1.46 M

how many milliliters of 0.550 m hi(aq) are needed to react with 15.00 ml of 0.217 m koh(aq)?

Answers

5.91 mL of 0.550 M HI(aq) are needed to react with 15.00 mL of 0.217 M KOH(aq).

The balanced chemical equation for the reaction between HI(aq) and KOH(aq) is: HI(aq) + KOH(aq) → KI(aq) + H₂O(l) According to the equation, the stoichiometry of the reaction is 1:1 between HI and KOH.

This means that 1 mole of HI reacts with 1 mole of KOH. To determine how many milliliters of 0.550 M HI(aq) are needed to react with 15.00 mL of 0.217 M KOH(aq), we need to use the equation: M₁V₁ = M₂V₂

where M₁ and V₁ are the concentration and volume of the HI(aq) solution, and M₂ and V₂ are the concentration and volume of the KOH(aq) solution, respectively. Rearranging the equation to solve for V₁, we get: V₁ = (M₂V₂)/M₁

Substituting the given values, we get:

V₁ = (0.217 mol/L × 0.01500 L)/0.550 mol/L.

V₁ ≈ 0.00591 L or 5.91 mL.

To know more about stoichiometry, refer here:

https://brainly.com/question/28780091#

#SPJ11

What quantity of hcl, in grams, can a tablet with 0.750 g of al(oh) 3 consume? what quantity of water is produced?

Answers

0.750 g of Al(OH)3 can consume approximately 1.04 g of HCl.

Also, approximately 0.514 grams of water would be produced in this reaction.

To determine the quantity of HCl consumed by 0.750 g of Al(OH)3, we need to consider the balanced chemical equation between Al(OH)3 and HCl.

The balanced equation is as follows:

2 Al(OH)3 + 6 HCl -> 2 AlCl3 + 6 H2O

From the balanced equation, we can see that 2 moles of Al(OH)3 react with 6 moles of HCl to produce 6 moles of water.

To calculate the quantity of HCl consumed, we need to convert the mass of Al(OH)3 to moles and then use the mole ratio between Al(OH)3 and HCl.

1. Calculate the number of moles of Al(OH)3:

  Moles = Mass / Molar mass

  Moles = 0.750 g / (26.98 g/mol + 3(16.00 g/mol))

  Moles = 0.750 g / 78.98 g/mol

  Moles ≈ 0.00949 mol

2. Use the mole ratio between Al(OH)3 and HCl (from the balanced equation) to determine the moles of HCl consumed:

  Moles of HCl = (0.00949 mol Al(OH)3) * (6 mol HCl / 2 mol Al(OH)3)

  Moles of HCl ≈ 0.0285 mol

3. Calculate the mass of HCl consumed:

  Mass = Moles * Molar mass

  Mass = 0.0285 mol * 36.46 g/mol

  Mass ≈ 1.04 g

Therefore, 0.750 g of Al(OH)3 can consume approximately 1.04 g of HCl.

Regarding the quantity of water produced, the balanced equation shows that 2 moles of Al(OH)3 react to produce 6 moles of water.

Since we have determined that 0.00949 mol of Al(OH)3 is consumed, the corresponding moles of water produced will be:

Moles of water = (0.00949 mol Al(OH)3) * (6 mol H2O / 2 mol Al(OH)3)

Moles of water ≈ 0.0285 mol

To calculate the quantity of water in grams, we multiply the moles by the molar mass of water:

Mass of water = Moles of water * Molar mass of water

Mass of water = 0.0285 mol * 18.02 g/mol

Mass of water ≈ 0.514 g

Therefore, approximately 0.514 grams of water would be produced in this reaction.

To know more about Molar mass refer here

https://brainly.com/question/12127540#

#SPJ11

if the half life of a radioactive element is years how many years will it take for a sample to decay to the point where its activity is of the original value

Answers

The activity of a radioactive sample decays exponentially with time, and the half-life is the time it takes for the activity to decrease to half of its original value.

If the half-life of a radioactive element is T years, it will take 2T years for the activity to decrease to 25% of its original value, 3T years to decrease to 12.5% of its original value, and so on.

To calculate how many years it will take for the activity to decrease to a certain percentage of the original value, one can use the formula A=A0(0.5)^(t/T), where A is the activity at time t, A0 is the initial activity, and T is the half-life. Solving for t, we get t = T log₂ (A0/A), where log₂ is the logarithm to the base 2.

To know more about the half-life refer here :

https://brainly.com/question/24710827#

#SPJ11

How many grams of HF form from the reaction of 42.0g of NH3 with 35.0 g of fluorine? 5F2 (g) + 2NH3 (g) --> N2F4 (g) + 6HF (g)

Answers

The amount of Hydrogen Fluoride that can be form from the given reaction is 22.08 g.

The balanced chemical reaction is given as,

5F₂ (g)  +  2NH₃ (g)  -->  N₂F₄ (g)  +  6HF (g)

According to the stoichiometry of the reaction

5 moles of F₂ reacts with 2 moles of NH₃

Given,

Mass of NH₃ = 42 g

=> Moles of NH₃ = 42 / 17 = 2.75 moles

Mass of F₂ = 35 g

=> Moles of F₂ = 35 / 38 = 0.92 moles

5 moles of F₂ reacts with 2 moles of NH₃

=> 1 mole of F₂ reacts with 2/5 = 0.4 moles of NH₃

=> 0.92 moles of F₂ reacts with 0.4 x 0.92 = 0.368 moles of NH₃

We see form the above calculations that NH₃ is present in excess of 2.75 - 0.368 = 2.38 moles

Hence F₂ is the limiting reagent of the reaction

From the stoichiometry 5 moles of F₂ reacts to produce 6 moles of HF

Hence,

0.92 moles of F₂ reacts to produce 0.92 x 6 / 5 = 1.104 moles of HF

=> Moles of HF produced = 1.104

=> Mass of HF = 1.104 x 20 = 22.08 g

Learn more about Mass from the link given below.

https://brainly.com/question/19694949

#SPJ4

a student is given a 50-ml volumetric flask to prepare a 0.15 m solution of the salt (molar mass = 20.163 g/mol). how many grams of the salt should the student dissolve?

Answers

To prepare a 0.15 M solution using a 50 mL volumetric flask, the student needs to dissolve 0.15 moles of the salt in the flask. To find the mass of the salt needed, we can use the formula:
mass = moles x molar mass

So, mass = 0.15 moles x 20.163 g/mol = 3.02445 g
Therefore, the student should dissolve 3.02445 grams of the salt to prepare a 0.15 M solution in a 50 mL volumetric flask.To prepare a 0.15 M solution of the salt (molar mass = 20.163 g/mol) in a 50 mL volumetric flask, the student should dissolve:

grams of salt = (0.15 mol/L) x (20.163 g/mol) x (0.050 L) = 0.15195 g
The student should dissolve approximately 0.15195 grams of the salt.

To know more about volumetric flask visit-

https://brainly.com/question/15289714

#SPJ11

how many moles of nitrogen are required to make 3.4 moles of ca(no2)2

Answers

6.8 moles of nitrogen are required to make 3.4 moles of Ca(NO₂)₂ due to the 2:1 molar ratio of nitrogen to Ca(NO₂)₂.

To determine the number of moles of nitrogen required to make 3.4 moles of Ca(NO₂)₂, we need to first determine the molar ratio of nitrogen to Ca(NO₂)₂.

From the formula of Ca(NO₂)₂, we can see that there are 2 moles of NO₂ for every 1 mole of Ca(NO₂)₂. Since each NO₂ molecule contains one nitrogen atom, there are also 2 moles of nitrogen for every 1 mole of Ca(NO₂)₂.

Therefore, to make 3.4 moles of Ca(NO₂)₂, we would need 2 × 3.4 = 6.8 moles of nitrogen.

To know more about the molar ratio refer here :

https://brainly.com/question/1792057#

#SPJ11

you have a sample of sulfuric acid with an unknown concentration and you perform a titration with sodium hydroxide to determine the concentration.

Answers

When determining the concentration of an unknown sulfuric acid solution, a titration can be performed with a known concentration of sodium hydroxide.

Here are some additional details that may be helpful in understanding the process of titration:

The reaction between sulfuric acid and sodium hydroxide is an acid-base reaction, which results in the formation of water and a salt (sodium sulfate).The balanced chemical equation for the reaction is: H2SO4 + 2NaOH → Na2SO4 + 2H2OThe indicator used in the titration can vary, but phenolphthalein is commonly used, as it changes from colorless to pink at the point of equivalence (when all the acid has reacted with the base).The concentration of the sodium hydroxide solution must be known in order to accurately calculate the concentration of the sulfuric acid solution using the volume of sodium hydroxide used.The concentration of the sulfuric acid solution can be expressed in units of moles per liter (M), which is also referred to as its molarity.

The titration involves adding small amounts of the sodium hydroxide solution to the sulfuric acid solution until the reaction between the two is complete, which is indicated by a change in color of the indicator used. The volume of the sodium hydroxide solution used in the reaction can then be used to calculate the concentration of the sulfuric acid solution.

Learn More About sulfuric acid

https://brainly.com/question/10220770

#SPJ11

calculate the molarity of 0.500 mol of na2s in 1.30 l of solution.

Answers

The molarity of 0.500 mol of Na₂S in 1.30 L of solution is 0.385 M.

To calculate the molarity, we need to divide the number of moles of Na₂S by the volume of the solution in liters. So, molarity = moles of solute ÷ volume of solution in liters.
Given, moles of Na₂S = 0.500 mol and volume of solution = 1.30 L.
Therefore, molarity = 0.500 mol ÷ 1.30 L = 0.385 M.
This means that there are 0.385 moles of Na₂S in every liter of the solution.

Molarity is an important unit of concentration and is used to describe the amount of solute in a given volume of solution. In this case, we can say that the Na₂S solution is relatively dilute, as it has a molarity of less than 1.0 M.

Learn more about molarity here:

https://brainly.com/question/8732513

#SPJ11

minimum uncertainty in the position of a proton moving at a speed of 4 * 10^6. (True or False)

Answers

The minimum uncertainty in the position of an electron moving at a speed of 4 x 10⁶ m/s is approximately 1.4 x 10⁻⁷ meters.

The minimum uncertainty in the position of an electron moving at a speed of 4 x 10⁶  m/s can be calculated using the Heisenberg uncertainty principle, which states that the product of the uncertainty in position and the uncertainty in momentum must be greater than or equal to Planck's constant divided by 4π.

Δx * Δp ≥ h/4π

Where Δx is the uncertainty in position, Δp is the uncertainty in momentum, and h is Planck's constant.

The momentum of an electron is given by the product of its mass and velocity, which is approximately 9.11 x 10⁻³¹ kg x 4 x 10⁶ m/s = 3.64 x 10⁻²⁴kg m/s.

Using this value and Planck's constant (h = 6.626 x 10⁻³⁴J s), we can solve for the minimum uncertainty in position:
Δx * 3.64 x 10⁻²⁴ kg m/s ≥ 6.626 x 10⁻³⁴ Js/ 4π
Δx ≥ (6.626 x 10⁻³⁴Js/4π) / (3.64 x 10⁻²⁴ kg m/s)
Δx ≥ 1.4 x 10⁻⁷ meters

Therefore, the minimum uncertainty in the position of an electron moving is 1.4 x 10^-7 meters.

Complete question:

What is the minimum uncertainty in the position of an electron moving at a speed of 4 times 10^6 m /s?

Learn more about Heisenberg's uncertainty at https://brainly.com/question/16941142

#SPJ11

1.Give the IUPAC names for the following compounds a) and b)
2. Click on all the following Newman projections that represent the most stable conformation of 2,2-dimethylbutane
3. There are 9 different isomer of C7H16. Name the 1 isomer of C7H16 that contains an ethyl branch on the parent chain.

Answers

1a) The IUPAC name for the following compound is 3-ethyl-4-methylhexane.

1b) The IUPAC name for the following compound is 2-chloro-3-methylpentane.

2) The most stable conformation of 2,2-dimethylbutane is the anti-periplanar conformation.

3) The isomer of C7H16 that contains an ethyl branch on the parent chain is 2-ethylhexane.

Explanations to the above written short answers are provided below,

1a) The parent chain contains six carbons, and the substituents are located at positions 3 and 4, respectively. The substituent at position 3 is an ethyl group (two carbons), and the substituent at position 4 is a methyl group (one carbon).

1b) The parent chain contains five carbons, and the substituents are located at positions 2 and 3, respectively. The substituent at position 2 is a chloro group, and the substituent at position 3 is a methyl group.

2) This has a staggered arrangement with a dihedral angle of 180 degrees between the two methyl groups.

3) The parent chain contains six carbons, and the ethyl group (two carbons) is attached to the second carbon. The remaining four carbons are arranged in a linear chain, with three methyl groups attached at positions 3, 4, and 5.

To know more about "IUPAC" refer here:

https://brainly.com/question/26757517#

#SPJ11

how would the 4d orbitals differ from the 3d orbitals?

Answers

In chemistry, orbitals are regions of space around the nucleus where electrons are most likely to be found. The principal quantum number (n) determines the size of the orbital and its distance from the nucleus, while the azimuthal quantum number (l) determines the shape of the orbital.

In the case of transition metals, which have partially filled d-orbitals, the difference between 3d and 4d orbitals lies in their energy levels and shapes.

The main difference between 3d and 4d orbitals is their energy level. 4d orbitals are higher in energy than 3d orbitals due to the increase in the principal quantum number from 3 to 4.

This means that electrons in the 4d orbitals are farther from the nucleus and experience less attraction to the positively charged nucleus. As a result, 4d electrons are more easily removed than 3d electrons, leading to the characteristic reactivity of transition metals.

Another difference is in the shape of the orbitals. The 3d orbitals have complex shapes, including a  and a four-lobed clover shape. In contrast, 4d orbitals are more diffuse and have a greater number of lobes.

This is due to the increased distance between the nucleus and the electrons in the 4d orbitals, which results in a larger spatial distribution of the electron density.

To know more about principal quantum number refer here

https://brainly.com/question/16746749#

#SPJ11

a weak acid ha has a pka of 5.00. if 1.00 mol of this acid and 0.500 mol of naoh were dissolved in one liter of water, what would the final ph be?

Answers

The final pH of the solution is 5.00.

First, we need to write the balanced chemical equation for the reaction between the weak acid (HA) and the strong base (NaOH):

HA + NaOH → NaA + H2O

where NaA is the sodium salt of the weak acid.

Since 0.500 mol of NaOH is added to 1.00 mol of HA, the amount of HA remaining after the reaction is (1.00 - 0.500) = 0.500 mol.

To calculate the pH of the solution, we need to use the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

where [A-] is the concentration of the conjugate base (NaA) and [HA] is the concentration of the weak acid (HA).

We can find [A-] by multiplying the amount of NaOH added (0.500 mol) by the stoichiometric coefficient ratio of NaA to NaOH (1:1), and then dividing by the total volume of the solution (1.00 L):

[A-] = (0.500 mol NaOH) / (1.00 L) = 0.500 M

To find [HA], we need to use the initial molarity of the acid (1.00 M) minus the amount of acid that reacted with NaOH (0.500 mol), divided by the total volume of the solution (1.00 L):

[HA] = (1.00 mol HA - 0.500 mol NaOH) / (1.00 L) = 0.500 M

Now we can plug in the values for pKa, [A-], and [HA] to solve for pH:

pH = 5.00 + log(0.500/0.500) = 5.00

Therefore, the final pH of the solution is 5.00.

To learn more about molarity, refer below:

https://brainly.com/question/8732513

#SPJ11

The rate constant for a certain reaction is 5.10 x 103 s. If the initial reactant concentration was 0.550 M, what will the concentration be after 12.0 minutes? a.550 M b.250 M c.150 M d.014 M

Answers

If the rate constant for a certain reaction is 5.10 x 103 s, and the initial reactant concentration was 0.550 M, then the concentration after 12.0 minutes will be approximately 0.014 M (option d).

To solve this problem, we need to use the first-order rate law equation:

ln([A]t/[A]0) = -kt

where [A]t is the concentration of reactant at time t, [A]0 is the initial concentration of reactant, k is the rate constant, and t is time.

We can rearrange this equation to solve for [A]t:

[A]t = [A]0 * e^(-kt)

Substituting the given values, we get:

[A]t = 0.550 M * e^(-5.10 x 10^3 s^-1 * 12.0 min * 60 s/min)

[A]t = 0.014 M

Therefore, the concentration of reactant after 12.0 minutes is d. 0.014 M.

It's important to note that the rate constant is a constant value that is specific to a particular reaction at a given temperature and pressure.

The concentration of reactants, on the other hand, can vary over time as the reaction proceeds. The rate constant is used to calculate the rate of the reaction at any given time, while the concentration of reactants is used to determine how much of the reactants are left at a particular time.

Learn more about rate constant at: https://brainly.com/question/29511879

#SPJ11

hosw to solve the change in entropy when 0.802 g of silicon is burned in excess oxygen to yield silicon dioxide at 298 k?

Answers

To solve for the change in entropy, we can use the equation:

ΔS = nS°(products) - mS°(reactants)

where:

- ΔS is the change in entropy

- n and m are the stoichiometric coefficients of the products and reactants, respectively

- S° is the standard molar entropy of the substance

First, we need to write the balanced chemical equation for the combustion of silicon:

Si + O2 -> SiO2

From the equation, we can see that the stoichiometric coefficient of silicon is 1. Therefore, n = 1.

Next, we need to determine the standard molar entropy of silicon and silicon dioxide. According to standard tables, the values are:

S°(Si) = 18.8 J/(mol K)

S°(SiO2) = 41.8 J/(mol K)

Now we can substitute the values into the equation:

ΔS = nS°(SiO2) - mS°(Si)

Since all the silicon is consumed, m = 0.802 g / (28.09 g/mol) = 0.0286 mol.

ΔS = 1(41.8 J/(mol K)) - 0.0286 mol(18.8 J/(mol K))

ΔS = 0.919 J/K

Therefore, the change in entropy when 0.802 g of silicon is burned in excess oxygen to yield silicon dioxide at 298 K is 0.919 J/K.

To know more about entropy refer here

https://brainly.com/question/13135498#

#SPJ11

concentrated sodium hydroxde (naoh) must be treated with caution because it is choose... . proper protective equipment includes choose... and choose... .

Answers

Concentrated sodium hydroxide (NaOH) must be treated with caution because it is a highly corrosive and caustic substance. Proper protective equipment includes chemical-resistant gloves and safety goggles.

Handling concentrated sodium hydroxide requires strict safety measures due to its potential to cause severe burns and damage to the skin, eyes, and respiratory system. In addition to chemical-resistant gloves and safety goggles, other protective equipment such as a lab coat, closed-toe shoes, and even a face shield can be used to minimize the risk of exposure. In case of accidental contact, it is crucial to have an eyewash station and safety shower nearby to quickly rinse off any NaOH that comes into contact with the skin or eyes.

Furthermore, it is essential to work in a well-ventilated area to prevent the inhalation of harmful fumes, and proper storage guidelines must be followed. Sodium hydroxide should be stored in a tightly sealed, labeled container, away from any acidic or flammable materials. Lastly, it is important to be knowledgeable about emergency procedures and first-aid measures to handle any potential accidents or incidents involving concentrated NaOH.

Know more about Concentrated sodium hydroxide here:

https://brainly.com/question/28612681

#SPJ11

Consider cobal (ii) chloride and cobalt (ii) iodide will disolve seeprately. will cobalt (ii) fluoride be more or less soluble than clhoride (ii) bromide?

Answers

Cobalt (II) fluoride will be less soluble than cobalt (II) chloride.

Solubility of a salt is influenced by several factors, including the nature of the ions involved and their relative sizes. In general, as the size of the anion increases, the solubility of the salt decreases. Similarly, as the size of the cation increases, the solubility of the salt also increases.

Comparing cobalt (II) fluoride with cobalt (II) chloride and cobalt (II) bromide, we can see that the fluoride ion (F⁻) is smaller than the chloride ion (Cl⁻) and bromide ion (Br⁻). This means that cobalt (II) fluoride has a higher lattice energy than cobalt (II) chloride and cobalt (II) bromide due to the stronger electrostatic attraction between the smaller fluoride ions and the cobalt (II) ions. This strong lattice energy makes cobalt (II) fluoride less soluble than cobalt (II) chloride and cobalt (II) bromide.

learn more about Solubility here:

https://brainly.com/question/31493083

#SPJ11

HBrO2 is a weak acid. What are the spectator ions in a neutralization reaction involving this weak acid and sodium hydroxide, NaOH? A. Nat(aq) only B. Nat(aq) and BrO2 (aq) C. H*(aq) and OH(aq) D. BrO2 (aq) only E. H*(aq) only t o

Answers

The spectator ions in a neutralization reaction involving this weak acid (HBrO2) and sodium hydroxide (NaOH) is Na+(aq) and BrO2-(aq).

The neutralization reaction between HBrO2 and NaOH can be represented as follows:

HBrO2  +  NaOH   →   NaBrO2   +  H2O

The complete ionic reaction is

H+BrO2-   +   Na+OH-   →   Na+BrO2-   +  H2O

The net ionic reaction is

H+    +   OH-    →       H2O

In this reaction, Na+ and OH- are the ions that combine to form NaOH and they are called the spectator ions because they do not participate in the formation of the products.

Therefore, the answer is option B. Na+(aq) and BrO2-(aq).

To know more about the spectator ions, click below.

https://brainly.com/question/15053039

#SPJ11

consider the reaction: ch4(g) 2 o2 (g) → co2(g) 2 h2o(l) \deltaδh = -890 kj if 0.30

Answers

The combustion of 0.30 g of methane produces -16.02 kJ of heat.

The given enthalpy change for the reaction is -890 kJ.

To calculate the amount of heat produced by the combustion of 0.30 g of methane, we need to first calculate the moles of methane used in the reaction;

1 mol CH₄(g) = 16.04 g

0.30 g CH₄(g) = 0.30/16.04 mol CH₄(g)

= 0.018 mol CH₄(g)

From the balanced chemical equation, we know that 1 mole of CH4(g) produces -890 kJ of heat. Therefore, the amount of heat produced by the combustion of 0.018 mol of CH₄(g) can be calculated as;

q = -890 kJ/mol × 0.018 mol

q = -16.02 kJ

Therefore, the combustion of 0.30 g of methane produces -16.02 kJ of heat. Note that the negative sign indicates that the reaction is exothermic and releases heat to the surroundings.

To know more about enthalpy change here

https://brainly.com/question/29556033

#SPJ4

--The given question is incorrect, the correct question is

"Consider the reaction: CH₄(g) 2O₂ (g) → CO₂(g) 2H₂O(l) \deltaδh = -890 kj. Calculate the amount of heat (q) produced by the combustion of 0.30 g of methane."--

if 1.15 g of water is enclosed in a 1.5 −l container, will any liquid be present? IF so, what mass of liquid?

Answers

Yes, liquid will be present. The mass of the liquid present will be 1498.85 g.

The density of water is approximately 1 g/mL or 1 g/cm³. Therefore, 1.15 g of water has a volume of 1.15 mL or 0.00115 L. Since the container has a volume of 1.5 L, there is still space for more liquid.

The container has a volume of 1.5 L, which is equivalent to 1500 mL or 1500 cm³. The volume of the water is 1.15 mL or 1.15 cm³. Therefore, the remaining volume of the container is 1498.85 mL or 1498.85 cm³.

Assuming that the container is completely filled with liquid, we can use the density of water to calculate the mass of liquid present.

Density = mass/volume

1 g/cm³ = mass/1498.85 cm³

mass = 1498.85 g

To learn more about density visit:

brainly.com/question/29775886

#SPJ11

How


many moles of Strontium Phosphate are in 55. 50 grams of Strontium Phosphate :


Sr3(PO4)2?

Answers

There are approximately 0.1229 moles of strontium phosphate in 55.50 grams of the compound.

To determine the number of moles of strontium phosphate [tex](Sr_3(PO_4)_2)[/tex] in 55.50 grams, we need to use the concept of molar mass and Avogadro's number.  First, we calculate the molar mass of strontium phosphate by summing up the atomic masses of each element present in the compound. Strontium (Sr) has an atomic mass of approximately 87.62 grams/mol, phosphorus (P) has an atomic mass of approximately 30.97 grams/mol, and oxygen (O) has an atomic mass of approximately 16.00 grams/mol.  So, the molar mass of strontium phosphate is:

3(Sr) + 2([tex](PO_4)[/tex]) = 3(87.62) + 2(30.97 + 4(16.00)) = 261.86 + 2(30.97 + 64.00) = 261.86 + 2(94.97) = 261.86 + 189.94 = 451.80 grams/mol

Next, we use the formula:

moles = mass / molar mass

Plugging in the given mass of 55.50 grams and the molar mass of 451.80 grams/mol:

moles = 55.50 g / 451.80 g/mol ≈ 0.1229 mol

Learn more about  molar mass here:

https://brainly.com/question/30640134

#SPJ11

Calculate ΔS° for the reaction SO2(s) + NO2(g) → SO3(g) + NO(g).
S°(J/K·mol)
SO2(g) 248.5
SO3(g) 256.2
NO(g) 210.6
NO2(g) 240.5

Answers

The standard entropy change for the reaction is ΔS° = 228.8 J/K·mol.

The standard entropy change, ΔS°, can be calculated using the following equation:

ΔS° = ΣS°(products) - ΣS°(reactants)

where ΣS° represents the sum of the standard entropies of the products or reactants, respectively.

Using the standard entropy values given:

ΔS° = [S°([tex]SO_3(g)[/tex]) + S°([tex]NO(g)[/tex])] - [S°([tex]SO_2(s)[/tex]) + S°([tex]NO_2(g)[/tex])]

ΔS° = [(256.2 J/K·mol) + (210.6 J/K·mol)] - [(248.5 J/K·mol) + (240.5 J/K·mol)]

ΔS° = 228.8 J/K·mol

For more question on standard entropy click on

https://brainly.com/question/30174483

#SPJ11

identify what occurs during an aldol condensation reaction - addition, elimination, substitution, oxidation-reduction? (3 pts)

Answers

During an aldol condensation reaction, both addition and elimination reactions occur. Oxidation-reduction and substitution reactions are not involved in this process.

Aldol condensation reaction involves the addition and elimination of a carbonyl compound, usually an aldehyde or ketone, under basic or acidic conditions. The reaction starts with the nucleophilic addition of the enolate ion of the carbonyl compound to another carbonyl compound, forming a beta-hydroxy aldehyde or beta-hydroxy ketone intermediate. This intermediate then undergoes dehydration through the elimination of a water molecule, resulting in the formation of an alpha,beta-unsaturated aldehyde, or ketone.

Therefore, aldol condensation is mainly an addition-elimination reaction, and there is no oxidation-reduction or substitution occurring during this process. In summary, a detailed and long answer would be that aldol condensation is a reaction where a carbonyl compound undergoes nucleophilic addition with another carbonyl compound under basic or acidic conditions, forming a beta-hydroxy aldehyde or beta-hydroxy ketone intermediate. This intermediate then undergoes dehydration, leading to the formation of an alpha,beta-unsaturated aldehyde, or ketone. There is no oxidation-reduction or substitution occurring during this process.

An aldol condensation reaction involves two main steps:
1. The addition of an enolate ion (generated from a carbonyl compound) to another carbonyl compound, forming a beta-hydroxy carbonyl compound (aldol).
2. Dehydration of the aldol, which is an elimination reaction, results in an alpha-beta unsaturated carbonyl compound.

So, during an aldol condensation reaction, both addition and elimination reactions occur. Oxidation-reduction and substitution reactions are not involved in this process.

Learn more about aldol reaction

https://brainly.com/question/28984750

#SPJ11

in the t test, s is used to estimate σ. true false

Answers

In the t-test, the sample standard deviation (s) is used to estimate the population standard deviation (σ) is true, because the population standard deviation is generally unknown and must be estimated from the sample data.

The t-test is a statistical hypothesis test that is used to determine whether there is a significant difference between the means of two groups. It is often used when the sample size is small and the population standard deviation is unknown. The t-statistic is calculated as the difference between the sample means divided by the standard error of the difference, which is calculated using the sample standard deviations and the sample sizes. The t-statistic is compared to a t-distribution with degrees of freedom equal to the sum of the sample sizes minus two, and the p-value is calculated based on the probability of observing a t-value as extreme as the calculated t-value assuming the null hypothesis is true.

Learn more about t-test: https://brainly.com/question/15870238

#SPJ11

1. What is the difference between waxing and waning?


A. The light is getting bigger when it's waning and smaller when


it's waxing


B. The light is getting bigger when it's waxing and smaller when


it's waning


C. Waxing means that there is no light and waning means that


there is light


D. Waxing comes after a Full Moon and waning comes after New


Moon

Answers

The correct answer is:

B. The light is getting bigger when it's waxing and smaller when it's waning.

Waxing and waning are terms used to describe the changing appearance of the Moon's illuminated portion as seen from Earth.

Waxing refers to the phase of the Moon when the illuminated area is increasing, starting from a New Moon and progressing towards a Full Moon. During the waxing phase, the Moon appears to grow larger and brighter.

Waning, on the other hand, refers to the phase of the Moon when the illuminated area is decreasing, starting from a Full Moon and progressing towards a New Moon. During the waning phase, the Moon appears to shrink in size and become less bright.

Therefore, the key difference between waxing and waning lies in the direction of change in the illuminated portion of the Moon. Waxing means the illuminated area is getting larger, while waning means the illuminated area is getting smaller.

to learn more about moon click here:brainly.com/question/30653068

#SPJ 11

Other Questions
Zoe is packaging a gift to send in the mail. A smaller gift box is placed inside a similar yet larger packaging box. The empty space inside the packaging box is filled with tissue paper to keep the gift box from moving. The dimensions of the larger box are each 2.1 times longer than the corresponding dimensions of the smaller box. The volume of the smaller box is 24 cubic centimeters. What is the volume of the space filled with tissue paper in the packaging box? 81.84 cubic centimeters 105.84 cubic centimeters 198.264 cubic centimeters 222.264 cubic centimeters [30 points] Read this excerpt from President Trumans State of the Union address in 1951:All free nations are exposed and all are in peril. Their only security lies in banding together. No one nation can find protection in a selfish search for a safe haven from the storm.The free nations do not have any aggressive purpose. We want only peace in the world--peace for all countries. No threat to the security of any nation is concealed in our plans and programs.We had hoped that the Soviet Union, with its security assured by the Charter of the United Nations, would be willing to live and let live. But I am sorry to say that has not been the case.The imperialism of the czars has been replaced by the even more ambitious, more crafty, and more menacing imperialism of the rulers of the Soviet Union.This new imperialism has powerful military forces. It is keeping millions of men under arms. It has a large air force and a strong submarine force. It has complete control of the men and equipment of its satellites. It has kept its subject peoples and its economy in a state of perpetual mobilization.The present rulers of the Soviet Union have shown that they are willing to use this power to destroy the free nations and win domination over the whole world.The Soviet imperialists have two ways of going about their destructive work. They use the method of subversion and internal revolution, and they use the method of external aggression. In preparation for either of these methods of attack, they stir up class strife and disorder. They encourage sabotage. They put out poisonous propaganda. They deliberately try to prevent economic improvement.Based on the excerpt you read in part A and the one you just read, how did Trumans attitude toward the Soviet Union change between 1946 and 1951? Support your answer with at least one quotation from each excerpt. At the worlds first womens rights convention in 1848, the most contentious issue proved to be? Norton loans a customer $500 on January 1. On July 1 of the same year, the customer must repay Norton $525. The amount of interest earned by Norton is $ . Describe how professional standards and competencies are incorporated into curricula. Tenemos un examen el prximo lunes, entonces...Estefana _____ escribe un correo electrnico a m y nuestros amigos.MeTeLeLesNos In general, what effect does a quota have on the prices of comparable goods in the domestic market? Part 1:A. Express the new length of the long side of the note card, once the two corners are removed.B. Express the new width of the short side of the note card, once the two corners are removed.Part 2:Write a function A(x) that defines the area of the bottom of the box, once the corners are removed and the sides are folded up. Part 3:A. Suppose you want the bottom of your box to cover a total area of 16 in2. Set up an equation in standard form that will help you find the size (x) of the corner you need to cut in order for your box to have this area. B. Solve this equation and take note of any extraneous solutions. Explain why the answer is extraneous, and clearly state the correct answer Assuming that everything else is equal, a U.S. government bond that matures 30 years from now most likely pays alower interest rate than a U.S. government bond that matures 10 years from now. A condition of the lymphatic system evidenced by inflammation of the lymphatic vessels with accompanying red streaks visible in the skin is called ____. Generally, the courts have the power to declare certain types of contracts _______ on the grounds that they are contrary to _______. (Choose two correct answers) Take some time to fill in your notes, the area that is not shown in this video. Fill in the table with the values you think are the x-values and the y-values, write them as ordered pairs, then write them as a ratio in y/x form. In the table, which are the y-values and which are the x-values [Time(s) or Heartbeat(s)]? The representation of a government to other foreign governments is called:________ According to the diathesis-stress model, monozygotic twins raised in the same household will:_____.A) not necessarily have the same disorders because of potential differences in their diathesis.B) have the same disorders because their diathesis and stress are exactly the same.C) not necessarily have the same disorders because of potential differences in their stress.D) have no more likelihood of sharing a disorder than any other two randomly selected individuals from the population. Multitasking is about paying attention, because without attention there can be no multitasking.True or False what does figurative mean ? Highlight each sentence and match them to the correct answer.Will you write me a letter?Can I come over to your house?Why is this here?3 optionsA - This is a question. It is trying to find something out, and it ends with a question mark. It starts with the question word will.B - This is a question. It uses the question word why. It is asking for an answer, and ends with a question mark.C - Even though it doesn't start with a question word, this is a question. It is asking for information, and ends in a question mark. Which function describes this graph? Please help with questions 1 and 2 thank you Of the various alliances discussed in the mini-case, which one, by pairing a u.s. firm with one based in istanbul, is clearly a cross-border strategic alliance?